Ultrafine particles [PM0.1 or nanoparticles (NPs)] are prevalent in the atmosphere, originating from fuel combustion and terrestrial vegetation. Inhaled NPs readily (1) travel through the lung airway to the end of the respiratory tree (alveolus), (2) diffuse through the layer of lung lining fluid that contains secreted proteins and immune cells that are recruited from the lung airway, and (3) enter various cell types that constitute the lungs. Depending on the composition of NPs, the interaction between the inhaled NPs and lungs may trigger an inflammatory response. Addressing the interactions of inhaled NPs along their respiratory journey will enrich our understanding in their potential health effects.

In this talk, we present an integrated approach to elucidating the "lung-nano" interactions of inhaled NPs by considering the interplay of three aspects, the (1) protein corona surrounding the inhaled NPs after exposure to lung lining fluid, (2) intrapulmonary cellular-level distribution of NPs, and (3) immune response triggered. Note that past related studies focused on only one (at most two) of these aspects. We subject mice to short-term, whole-body inhalation of NPs. To track the dynamics of intrapulmonary distribution of NPs (at both tissue and cellular levels) and immune response, we sacrifice the mice for collecting their BALF and lavaged lung tissues at different time points post-inhalation. In parallel, we analyze the composition of the adsorbed proteins on the NPs upon immersion in bronchoalveolar lavage fluid (BALF) extracted from mice. Based on these data, we generate a table of adsorbed BALF proteins, lung or immune cells that internalize NPs, and pro-inflammatory markers with significant correlation. For our model NPs, we choose ~50 nm polyethylene glycol-coated gold NPs that bear methoxy (-OCH3) groups because of their frequent use in nano-bio studies. Given the diverse molecular composition of atmospheric NPs, we repeat our studies with NPs that contain four other types of functional groups commonly found in atmospheric particles.